1. Field of the Invention
The present invention relates to a plastic injection mold, and more particularly, to a side action mechanism of the injection mold.
2. The Related Art
In injection molding, upper and lower mold halves are brought together to define a mold cavity into where heated molten plastic is injected under pressure. The mold halves are typically vertically aligned with an upper mold portion termed the cavity half and a lower mold portion termed the core mold half. For forming holes or apertures or undercut through sides or on other location of molded pieces, side action mechanism are provided which are projected into the molding cavity as the mold halves are closed and which must be retracted from the cavity as the mold is opened and before ejection of the part can take place.
A conventional side-action mechanism 90a shown in FIG. 9 includes an insert core 91a and a side core 92a. The insert core 91a further includes a secured portion 911a, an insert portion 912a extending slantingly from the secured portion 911a. The side core 92a which cooperates with the insert core 91a further has a slide portion 921a with a slide groove 924a defined therein. The slide groove 924a is used for accommodating the insert portion 912a paralleling to the insert core 912a. An arm 922a extends forwards from the slide portion 921a and further defines a core element 923a at its free end. When the injection mold is closed, the insert portion 912a is fully inserted in the slide groove 924a, and the core element 923a is put in a mold cavity. At the open process of the injection mold, the insert portion 912a withdraws from the slide groove 924. At the same time, the core element 923a is retracted from the mold cavity.
One problem with current side-action mechanism is that the angle between the insert core 91a and the side core 92a is too big. As a result, the closing and opening forces of the mold by the press are relatively great and create great frictional resistance between the slide groove 924a and the insert core 912a. The insert core may not be able to overcome the frictional resistance before it fails. Accordingly, there is a need for a side-action mechanism which is more forgiving in terms of the tolerances required for trouble-free operation side-action mechanism.